1. Field of the Invention
The present invention is related to industrial fire fighting using thrown streams of firefighting agents, and more particularly, including the use of dry powder firefighting agents applied together with fluid mixtures including foam.
2. Background of the Invention
Commercial fighting of industrial fires, and particularly fires which include a replenishing source of flammable material (three dimensional or dynamic fires), may require the use of a plurality of fire fighting agents. These agents may be thrown or applied simultaneously, at least at times, either in adjacent streams or intermixed. In industrial fires generally, streams are thrown from nozzles at an approximate minimum of 95 gallons per minute (GPM) and frequently at much higher rates. However, in certain specific industrial applications, lower throw rates may be required: i.e. in air crash rescue fires the rate of throw is in the range of 35-60 GPM, while for offshore use throw rates of 60-120 GPM are employed. The present invention is applicable in all of these industrial situations.
One key example includes the use of dry chemicals in addition to liquids and liquid/foam mixtures. Dry chemicals are difficult to apply in a long distance stream. Further, dry chemicals have limited usefulness when applied alone primarily because they are not able to cool the fire and thus prevent reignition. Conversely, while liquids are able to control the heat and reduce the size of three dimensional fires, they are less effective than dry powder in controlling the chemical combustion that may sustain fires which have a continuing source of flammable material. Thus, U.S. Pat. No. 5,167,285 ('285) discloses a nozzle capable of simultaneously applying both liquid and dry powder.
The '285 nozzle, marketed under the tradename, "HydroChem", throws a stream of dry powder or chemical within a stream of liquid or foam by injecting the dry powder or chemical stream into the middle of the liquid or foam solution stream at the nozzle discharge port. The dry chemical stream is projected with and, to a certain extent, by the liquid/foam stream. When simultaneously dispensed by HydroChem nozzles, liquid agent streams are able to carry desired dry chemical streams to a fire apparently by entrapping, encapsulating, or entraining them within the fluid stream. Yet, the chemical performs like a "dry" chemical at the fire. Such transport with or in the liquid stream has enabled application of dry chemical agents from considerably greater distances than was previously possible.
Liquid/water mixtures are typically thrown continuously at fires using a high volume and velocity. When special agents such as dry chemicals are used, they are typically applied briefly and in small quantities at critical points during a firefighting episode. Because dry chemical agents are only available and used in small quantities relative to the volume of liquid and foam used, it would be highly desirable to be able to optimize the orchestration of their use. When the standard chemicals are applied simultaneously today, it is currently quite difficult to determine when and to what extent the special agents, such as dry chemicals, are present in the fluid stream and reaching the target. Neither the throw nor the footprint of the thrown special agent is visible using currently available formulations. Verification as to the presence of special agents in the thrown stream and the trajectory of these agents is of importance both to the individual operators of the fire extinguishing nozzles and to the director of the fire fighting team.
Liquid/foam mixtures currently used are either translucent, white, or gray. While dry powders having some coloration are commercially available for use in extinguishing fires, the coloration of such powders is currently insufficient for the dry chemical constituent to be readily visually apparent when thrown simultaneously with a water and/or foam stream. For example, Purple-K [PK] Dry Chemical Powder is known for use in extinguishing chemical fires and comprises potassium bicarbonate based dry chemical containing a purple pigment. Nevertheless, because of its relatively pale coloration, when Purple-K is thrown from a nozzle together with foam, the operator is unable to distinctly visually determine whether, where, or for how long, the powder is present in the stream.
When thrown with liquid or foam, currently available Purple-K powder is essentially undetectable within the fluid stream such that the only way that the presence of the powder in the stream is surmised is that after several seconds of application, some substance can be detected rather drifting in the air instead of more straightforwardly falling to the ground as fluid typically does. A fluid stream which contains a burst of dry powder usually ultimately attains a more foggy diffuse appearance. However, the fire director or pointer who coordinates the actions of the individual firefighters is unable to straightforwardly and immediately detect the presence of Purple-K in the liquid/foam stream, much less determine that the dry chemical is carrying to the target area. Further, the inability to immediately identify the presence of the powder potentially results in longer and injudicious use of the dry chemical agents such that this limited resource may be depleted too soon. A nozzle's supply of dry powder typically lasts only about 15 seconds. The coloration in available dry powders has historically been insufficient to provide a solution to these important problems.
This invention discloses the use of a violently or vividly colored special fire fighting agent, such as a dry chemical formulation which, contains sufficient pigment that a viewer of a thrown stream can readily visually determine the presence or absence of the agent, and its trajectory, when it is thrown simultaneously with other agents such as water or foam. Thus, an operator can appraise the extent to which the special agent is being acquired by the equipment and projected into the thrown stream. Fire pointers can assess the distance that the special agent is projected and the extent to which it is reaching the target area and, if desired, can optimize the orchestration of the use of bursts of dry chemical from the multitude of nozzles typically used in fighting an industrial fire. The invention applies equally to other agents or chemicals that might be included in or with a fire fighting stream, and might be thrown simultaneously with other fluids, and whose presence and extent of throw would be valuable to determine visually as the combined streams are applied. Dry chemical is the paradigmatic example.
The present invention discloses improved methods and compositions for use in the simultaneous application of two or more firefighting agents in a fluid stream wherein the addition of a visually distinctive coloration to an agent permits the operator of the equipment to readily visually appreciate the presence or absence of desired constituents in the stream. The method and compositions disclosed herein permit the judicious use of special fire extinguishing agents, including dry chemicals, and allows the firefighting team to coordinate the attack on the fire with an efficiency not previously possible. In the acute emergency of an industrial fire, it is crucial that the fire fighting team is easily aware of the presence and targeting of critical fire extinguishing agents. This invention discloses a simple, inexpensive real-time method and composition for acquiring this information.